1. Field of the Invention
The present invention relates to a circuit board, and particularly, to a circuit board with shielding layers enclosing the signal circuit layer.
2. Description of Related Art
Taiwan Patent No. 1337839 issued on Feb. 21, 2011 discloses a circuit board. The circuit board comprises a base board with a number of circuits printed thereon, a grounding port electrically connected with the circuits and at least one conductive plate extending from one edge of the base board and electrically connecting the grounding port. The circuit board is positioned in a metallic device with the conductive plate attached to the metallic device to achieve shielding effect. However, after assembly, the circuit board occupies too much space due to the metallic device. It is inconvenient for the layout of other components. Besides, a punching mold is needed to manufacture the metallic device with high cost.
Hence, an improved circuit board is desired to overcome the above problems.